When a brake pedal is pressed down, a stop lamp is turned on, and when the pedal is released, the lamp is turned off. In recent years, this kind of push type vehicle switch has been widely used for controlling a stop lamp when the brake pedal is operated. A conventional vehicle switch of this type is described with reference to FIG. 7.
FIG. 7 is a cross sectional view of a conventional vehicle switch. Case 1 made of insulating resin and formed essentially in a box shape has an opening at its top portion. Operating body 2 is accommodated in case 1 movably in up and down directions. Magnet 3 is attached to a lower left side of operating body 2. Terminals 4 are made of metal, and a lower end of each of terminals 4 is projected downward from a bottom of case 1. Wiring board 5 is disposed in a left side of operating body 2 inside case 1. On left and right sides of wiring board 5, wiring patterns (not illustrated) are formed. An upper end of terminal 4 is connected to the one of the wiring patterns of wiring board 5 by soldering, for instance.
On wiring board 5, detector 6 composed of a hall element is formed facing magnet 3. On wiring board 5, switching part 7 composed of a power transistor, and controller 8 composed of an FET, resistors and the like are also formed. Detector 6 and switching part 7 are connected to controller 8.
Controller 8 switches switching part 7 in response to a magnitude of magnetism detected by detector 6. When a magnetic flux density detected by detector 6 is a predetermined value or greater, controller 8 puts switching part 7 in a closing status and when the flux density is less than the predetermined value, controller 8 puts it in an opening status.
Spring 9 in a coil shape is disposed slightly compressed between a bottom face of operating body 2 and an inner bottom of case 1, resiliently pushing operating body 2 upward. Cover 10 made of insulating resin covers the opening of case 1 at the top. An upper end of operating shaft portion 2A of operating body 2 is protruding upward through cylindrical part 10A which is formed at an upper center part of cover 10. Vehicle switch 15 is constituted as described. Switch 15 is installed interlocked with a brake pedal, for turning on and off of a stop lamp (not illustrated).
When operating shaft portion 2A is pressed, operating body 2 is pushed down while compressing spring 9. Magnet 3 attached to the left side of operating body 2 is then moved down. With this movement, a center of magnet 3 facing a center of detector 6 is largely separated, making the magnetic flux density of magnet 3 detected by detector 6 minute. In this way, when operating body 2 is pushed down, switching part 7 is put in an opening status, keeping the stop lamp in an off status.
When the press-force applied to operating shaft portion 2A is removed, operating body 2 is pushed upward by a resilient restoring force of spring 9. Magnet 3 attached to operating body 2 then moves upward and magnet 3 faces detector 6. At this time, the magnetic flux density of magnet 3 detected by detector 6 becomes large. Controller 8 thus switches switching part 7 to the closing status, turning the stop lamp on.
Namely, when a driver operates a brake pedal and moves operating body 2 up and down, controller 8 switches the on/off status of switching part 7 in response to a magnitude of the magnetism of magnet 3 attached to operating body 2. With this operation, the stop lamp is turned on and off.
The brake pedal is usually attached to a lower end of an arm (not illustrated). An upper end of the arm is attached to a vehicle, serving as a fulcrum. The arm, therefore, turns around the fulcrum. Because of this constitution, when the upper end of operating shaft portion 2A of switch 15 is contacted with the arm, the end of shaft portion 2A is obliquely pressed. With this structure, operating body 2 moves up and down slanting in a small gap between an outer peripheral part of operating shaft portion 2A and an internal peripheral part of cylindrical part 10A. It causes a positional discrepancy of magnet 3 to detector 6, and therefore, an error in detecting magnetism of magnet 3 will occur when operating body 2 moves up and down.